The present invention relates to a controller and a control method for an internal combustion engine, provided with a plurality of detected units provided in a rotation member, which rotates integrally with a crankshaft, at a plurality of preliminarily set crank angles, and a specific crank angle sensor which is fixed to a nonrotation member and detects the detected unit.
In order to improve the fuel consumption performance and the emission performance of the internal combustion engine, the method of measuring the combustion condition of the internal combustion engine and carrying out feedback control of the measuring result is effective. For that purpose, it is important to measure the combustion condition of the internal combustion engine accurately. It is known widely that the combustion condition of the internal combustion engine can be measured accurately by measuring the cylinder internal pressure. However, since the sensor (hereinafter, the cylinder internal pressure sensor) which measures the cylinder internal pressure directly is very expensive, it is considered that it is difficult to use the cylinder internal pressure sensor for the commercial automobile internal combustion engine. As a technology of estimating the combustion condition of the internal combustion engine instead of the cylinder internal pressure sensor, Japanese Patent Application Publication No. 2009-275618 (JP-A-2009-275618) discloses a technology in which calculates a crank angle speed and a crank angle acceleration based on the output signal of the crank angle sensor, calculates a combustion gas pressure torque which was produced by combustion based on the crank angle speed and the crank angle acceleration, and estimates the combustion condition by the combustion gas pressure torque.